The Dornier Do 13 was a short-lived 1930s Germanbomber design. It was the designation given to the aircraft resulting from attempts to improve on the Do 11. However, only a few were built, because the design changes caused serious problems, with many of the first flights ending in crashes. Another redesign ensued, resulting in the Do 23, which later served in World War II in the Czech branch of the Luftwaffe. Do 13s under construction were converted to the Do 23 design.